1. Field
The present disclosure generally relates to optical communication and, more particularly, to optical engines and optical cable assemblies incorporating optical engines providing duty cycle correction.
2. Technical Background
As the data rate of communication protocols increases, it becomes difficult to transmit signals using purely electrical cables. Optics has provided a solution to the distance versus data rate problem for the telecommunication and data center markets. Benefits of optical fiber include longer reach, extremely wide bandwidth, and low noise operation. Because of these advantages, optical fiber is increasingly being used for a variety of applications, including, but not limited to, broadband voice, video, and data transmission. Optical fiber is emerging as the lowest cost and most compact interconnect technology in an increasing number of consumer electronics applications, especially at lengths greater than a few meters.
Some data transmission interfaces require low-speed data (e.g., control data at data rates such as 1 Mb/s) to be transmitted simultaneously with high-speed data (e.g., 10 Gb/s and beyond). However, the additional low-speed data require an additional transmission medium, such as copper conductors or additional optical fibers. The additional transmission medium may increase the diameter of the optical cable, and, in the case of copper conductors, require DC isolation between ends of the optical cable as well as provide additional shielding requirements due to electro-magnetic interference concerns. Further, intercepting and retransmitting low-speed data over optical fibers may be costly due to the strict timing requirements placed on the microcontroller by the communication protocol. Additional optical fibers for low-speed transmission may increase the cost of the optical cable.
In some cases, duty cycle distortion may occur with respect to low-speed data transmission. For example, sources of duty cycle distortion may include components that have uneven rise and fall times or different high-to-low and low-to-high digital signal decision thresholds. In the case of optical transceiver devices, duty cycle distortion may also arise if the response time between the electrical and optical signals (and vice-versa) is different in the case of a rising edge or a falling edge. Duty cycle distortion may introduce errors into the low-speed data signal.